题解 | #含有无关项的序列检测#

暴力求解，序列检测器要求检测几位，那就把那几位的值给保留下来。

注意题目还有一个坑：011XXX110的最后一位0不是刚进来的a，这个坑写代码时看时序应该能分析出来。

`timescale 1ns/1ns
module sequence_detect(
	input clk,
	input rst_n,
	input a,
	output reg match
	);

reg a1,a2,a3,a4,a5,a6,a7,a8,a9;
always @(posedge clk or negedge rst_n) begin
   if (!rst_n)begin
      match<=1'b0;
	  a2<=1'b0;a3<=1'b0;a4<=1'b0;a5<=1'b0;a6<=1'b0;a7<=1'b0;a8<=1'b0;
	  a9<=1'b0;a1<=1'b0;
   end
   else begin
      if ((!a1)&a2&a3&a7&a8&(!a9))match<=1;
	  else match<=1'b0;
      a9<=a8;
      a8<=a7;
      a7<=a6;
      a6<=a5;
      a5<=a4;
      a4<=a3;
      a3<=a2;
      a2<=a1;
	  a1<=a;
   end
end
  
endmodule